Conveying apparatuses for shelf channels of rack storage facilities of the kind discussed herein usually comprise two parallelly arranged, circulating conveying means by means of which the goods can be loaded into and unloaded from the individual shelf channels. The one half of the conveying means receiving the goods to be loaded is designed, in most cases, as a roller or supporting roller chain, while the other half is designed as tape. This arrangement lowers the costs and saves weight. However, such a design requires that one of the deflections must be adapted to a chain and the other one to a tape. In practice, the result is that the path of displacement of the chain is strictly limited to a value that is less than the distance between the centers of the front and the rear displacement, while the total length of the particular shelf channel is more than this distance. Thereby, there is a high risk that the path of displacement induced by the unloading vehicle during loading and unloading of goods is greater than the predetermined path of displacement of the conveying means. Thereby, the conveying means and/or the deflections often is/are damaged because the forces exerted by an unloading vehicle, e.g. a fork lift truck, can be very high.
Thus, the necessity is compellingly given that the chain is longer than the distance between the centers of the deflections. However, in the existing systems, this is not possible because the particular deflection can deflect only either the chain or the tape.
A further problem arising in connection with such conveyors consists in that the two conveying means, e.g. during the loading of goods, are very frequently not parallelly moved, but the one conveying means is forwarded somewhat more than the other one. Small differences can sum up in time to a great offset between the two conveying means, thereby further increasing the danger of a damage.
In order to ensure a reliable non-positive connection between the pallets put onto the conveying means and the chains, the individual chain links are provided with acute projections which engage the wooden material of the pallets. In this connection, a further well known problem arises inasmuch as the individual chain links rotate in relation to each other upon deflection. Such rotation leads to a relative displacement of the projections from one chain link to the other one. Since the pallet simultaneously rests both on the chain links rotating away during deflection as well as on the immediately subsequent horizontal chain link, wooden splinters are broken out of the pallet during the deflection operation. It is understood that this is undesired.
Thus, it is a task of the invention to propose a conveying apparatus for shelf channels of rack storage facilities that can be manufactured at low costs and simultaneously ensures a gentle, reliable and safe operation.